Motor control system with dynamic braking



May 20, 1952 1.. s. RILEY MOTOR CONTROL SYSTEM WITH DYNAMIC BRAKING 4Sheets-Sheet 1 Filed May 28, 1949 .7 no N10 wo- 2', INVENTOR 4 Lynn 6..Riley.- W

ATTORN May 20, 1952 s. RILEY 2,597,183

MOTOR CONTROL SYSTEM WITH DYNAMIC BRAKING Filed May 28, 1949 4Sheets-Sheet 2 INVENTOR Lynn G.Riley.

Flg.lB.

ATTOR Y May 20, 1952 G. RILEY MOTOR CONTROL SYSTEM WITH DYNAMIC BRAKING4 Sheets-Sheet 3 Filed May 28, 1949 x mm mm m m mm E 1 mm E mm -m E KKkK rm mm V 8 R4 mR m N EG M V N n "H I n A W L WITNESSES: (a WL May 20,1952 L. G. RILEY MOTOR CONTROL SYSTEM WITH DYNAMIC BRAKING 4Sheets-Sheet 4 Filed May 28. 1949 INVENTOR Lynn G.Ri ley.

ATTORN no Q fi w u sl HD1018 pun saves a mn WITNESSES:

Patented May 20, 1952 MOTOR CONTROL SYSTEM WITH DYNAMIC BRAKING Lynn G.Riley, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application May 28,1949, Serial No. 95,904

Claims. 1

My invention relates, generally, to control systems, and, moreparticularly, to systems for con trolling the operation of thepropelling motors of electric vehicles, such as, for example, the systemdescribed in the copending application of L. G. Riley and G. R. Purifoy,Serial No. 28,618, filed May 22, 1948, patented September 19, 1950, No.2,523,143.

It has been found that when the aforesaid system is utilized to controlcars operated in multiple-unit trains, certain imperfections in carcircuits, such as faulty coupler contacts for the train line wires,cause rapid chattering of some of the switch units under load. Thisresults in arcing of the switch contact members and may continue untilthe unit is destroyed.

An object of my invention, generally stated, is to provide a motorcontrol system which shall be simple and efiicient in operation andwhich may be economically manufacture and installed.

A more specific object of my invention is to protect the apparatus of acontrol system against faults in train line wires which extend throughthe cars of a multiple-unit train.

Another object of my invention is to ensure the correct positioning ofthe motor reverser, line switch and interlocks on certain of theswitches of the control system.

A further object of my invention is to ensure that the residual voltageof the motors will be of the correct polarity for dynamic braking.

Still another object of my invention is to provide an indication of anypower or dynamic brake failure caused by fault conditions in train lineor interlocking circuits.

Other objects of my invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

In accordance with my invention, a protective relay is so connected in amotor control system that it will permit a dynamic brake applicationonly after a normal power application, thereby ensuring continuity ofall main control circuits and correct polarity of residual motorvoltage.

For a better understanding of the nature and objects of my invention,reference may be had to the following detailed description, taken inconjunction with the accompanying drawings, in which:

Figures 1A, 1B, 1C and 1D, when combined, constitute a diagrammatic viewof a control system embodying the principal features of my invention;

Fig. 2 is a schematic diagram showing the main circuit connections forthe motors and the control apparatus; and

Fig. 3 is a chart showing the sequence of operation of part of theapparatus illustrated in Figs. 1 and 2.

Referring to the drawings, two motors MI and M2 may be utilized forpropelling an electric vehicle, such as, for example, a subway car (notshown). The motors are of the series type having armature windings IIand i2 and series field windings l3 and I4, respectively. A line switchLSI is provided for connecting the motors to a current collecting deviceI5 which engages a trolley conductor l6. A switch G is provided forconnecting the motors to a ground connection I 1, thereby completing thecircuit to a source of power such as a power generating station (notshown).

As indicated in the sequence chart in Fig. 3, the motors MI and M2 arefirst connected in series-circuit relation and then in parallel-circuitrelation during acceleration of the vehicle. In addition to the switchesLSI and G, a switch JR is provided for connecting the motors inseries-circuit relation. Bridging transition of the motors is obtainedby means of a switch J which is closed during the transition period. Theparallel-circuit connections are established through the switches LSI, Gand a double pole switch MG. A switch LS2 is provided for shunting aresistor I8 from the motor circuit on the second notch or step of theaccelerating cycle, as indicated in the sequence chart. The switch Jshunts a resistor 20 from the motor circuit just prior to the transitionfrom series to parallel operation.

The motors may also be connected for dynamic braking with the fieldwinding l4 connected across the armature winding H and the field windingI3 connected across the armature winding 12, thereby permitting thecurrent in the armature windings to reverse and cause the motors to actas generators and retard the vehicle. In addition to the switch MG,which is closed during dynamic braking, switches Bl, B2, B3, B4, B5 andB6 are utilized to establish the dynamic braking circuits and to controlthe motor current by shunting a resistor Hi from the motor circuitsduring dynamic braking.

The motor current during both acceleration and dynamic braking iscontrolled by resistors 2| and 22. Double pole resistor shuntingswitches RI, R2, R3, R4 are provided for shunting the resistors 2| and22 step-by-step. The resistor shunting switches operate in sequentialrelation, the sequence being controlled by interlock pro- 0 gression ina manner well known in the art.

The operation of the resistor shunting switches variable load mechanismin accordance with the load on the vehicle in a manner well known in theart.

As indicated in the drawings, the rheostat 24 may be adjusted by meansof a braking controller BC which is operated during dynamic braking.

If desired, the rheostat 24 may be adjusted in the manner described inPatent No. 2,318,330, issued May 4, 1943 to G. R. Purifoy, therebycoordinating the operation of the air-brake system and the dynamicbraking of the vehicles. As described in the aforesaid patent, anair-operated device is provided on each vehicle of a train for actuatingthe rheostat on each vehicle. These devices are connected to the airline of the air-brake system and each device is, therefore, responsiveto the'air-brake pressure which, in turn, is controlled by the brakincontroller BC. In order to simplify the present drawings, the air lineconnections have been omitted.

The relay OR is also provided with a braking rate coil BRC which'isconnected across a portion of 'a resistor 25 which is connected in themotor circuit during dynamic braking. Thus, the calibration'of the'relayCE is changed during dynamic braking by the efiect of the coil BRC.

An accelerating controller AC is provided for controlling the operationof the motor connecting switches during acceleration of the vehicle. Thecontroller AC maybe of the drum-type and, as shown, is provided withfour positions, namely, ofi, switching, series and parallel.

A reversing controller R is provided for controlling the direction ofoperation of the motors. The controller R controls the energization ofreversing switch coils FS and RS which, in turn, control the operationof the reversers for the motors Ml andMZ.

In order to permit the present system to be utilized on cars whichareoperated in multipleunit trains-and controlled from one control stationat the head of the train, a braking relay BR is provided. The relay BRpermits dynamic braking to be established simultaneously on all the carsof the train. The energization of the relay ER is controlled by thebraking controller BC which, as explained hereinbefore, may also beoperated to control the air-brake system which has not been shown. Thus,when the braking controller at the head of the train is operated, all ofthe relays BR throughout the train are energized to cause dynamicbraking to be established on all the motors in the train.

As shown, the controllers AC and BC are connected to train line wires L2, 3, 4, 5, 6, I and GS which extend throughout the train and areconnected together between cars through train line couplers. Thecontrollers AC and BC are electrically interlocked to prevent improperoperation of the equipment.

Provision is made for shunting the series field windings of the motorsduring portions of the accelerating and the braking cycles by means ofmultiple step controllers F01 and FCZ. As shown, the controllers FCI andFCZ may be actuated by an air engine PC which is provided with magnetvalves SF and FF for controlling the fluid pressure in the air engine.

The shunt circuit for the field winding l3 comprises a resistor 26 and areactor 21. As shown, the resistor 26 may be shunted step-bystep bymeans of the controller FCI. The shunt circuit for the series fieldwinding [4 comprises a resistor 28 and a reactor 29. The resistor 28 maybe shunted step-by-step by the controller 1 02. As explainedhereinbefore, the controllers FCI and FCZ may be operated simultaneouslyby the air engine FC. The controller FCI is provided with auxiliarycontact segments 3!, 32, 33 and 34, the function of which will beexplained more fully hereinafter.

In the power-off or coasting position of the controller AC, the dynamicbrake circuits are established and, at any speeds below a predeterminedspeed, the field shunt notching will progross at a low braking currentunder the control of a spotting relay'SR. As shown, the actuating coilof the relay SR is connected across a portion of the resistor 25 whichis in the dynamic braking circuit. Thus, the relay SR is responsive tothe vehicle speed since the voltage drop across the resistor 25 varieswith the current through the resistor which, in turn, is proportional tothe vehicle speed. Therefore, the control equipment is positioned inaccordance with the car speed and is prepared to respond promptlywhenever a brake application is called for. The spotting relay controlsthe operation of the field shunting controller FC during the spottingoperation.

While the basic spotting system affects only the position of the fieldshunt controller, spotting may take place on any of the series resistornotches depending on the shut-oil speed and the length of the coastingperiod. In general, the spotting relay will select the proper notch,depending on the field strength required to get spotting currentresponse. Two-way spottlng'oi the field controller insures properpositioning of the equipment within a short time after closing thecoasting circuits. Brake response is secured by building up fieldstrength and by resistor notches depending on the braking rate desired.A time delay relay TD is provided for delaying the operation of theresistor shunting switches for a short tim interval after full dynamicbraking is called for in order to insure that the field strength of themotors has had time to'build up.

In order to protect the equipment against faults in any of the basictrain line wires, I, 2, 3,6 and GS, a relay BP is provided. The relay BPhas a closin coil CC and a holding coil HC. The relay must be closedduring power operation to set up the spotting and braking motor circuitsand must stay closed throughout the entire braking cycle.

The closing coil CC is energized through train line wire 6 during poweroperation only after the line switch LSI and the switch G have closed,thereby ensuring the continuity of the train line wires l, 2, 6 and GS,as well as the correct positioning of the reverser, the line switch andthe interlocking switches actuated by these switches. The holding coilI-IC, which is not powerful enough to actuate the relay, is energizedthrough a continuation of the train line wire 3 beyond the interlocks onthe reversing switches and holds the relay closed upon a power shutofibecause of the overlap between the contact segments on the acceleratingcontroller just ahead of the oil position.

The contact members of the relay BP are so connected in the controlcircuit that a dynamic braking application can be obtained only after anormal power application, thus ensuring continuity of all controlcircuits and correct polarity of the residual motor voltage for buildingup a dynamic braking current. The relay BP is provided with normallyclosed contact members BPI which control the energization of anindicator light L through a switch S, thereby indicating the failure ofthe equipment to respond to power or brake applications.

In order that the functioning of the foregoing apparatus may be moreclearly understood, the operation of the system will now be described inmore detail. Assuming that it is desired to accelerate the vehicle atthe maximum rate, the controller AC is actuated to the parallelposition, thereby obtaining automatic operation of the controlequipment.

When the controller AC is on the switching position, the switches SLI, Gand JR are closed to connect the motors MI and M2 in series-circuitrelation and in series with the resistors I8, 20, 2I and 22. Theenergizing circuit for the actuating coil of the switch LSI may betraced from positive at the controller AC through a segment 35,conductor 36, a segment 31 on the reversing controller R, conductor I,an interlock 42 on the reversing switch RS, conductor 38, interlock BI3on the switch BI, conductor 39, interlock B56 on the switch B5,conductor 4| and the actuating coil of the switch LSI to negative. Theenergizing circuit for the actuating coil of the switch G extends fromthe controller segment 35 through conductor GS, an interlock B24,conductor 43, the actuating coil of the switch G and an interlock MGI onthe switch MG to negative. A holding circuit for the switch G isestablished through an interlock 64 on the switch G. Following theclosing of the switches LSI and G, the actuating coil of the switch JRis energized through a circuit which extends from the controller segment35 through conductor 6, an interlock LSI3, conductor 44, an interlockG3, conductor 45, an interlock MG3, conductor 46, an interlock J4,conductor 41 and the coil of the switch JR to negative.

At this time, the closing coil of the relay BP is energized through acircuit which extends from the previously energized conductor 45 throughthe closing coil to negative. It will be noted that it is necessary forthe switches LSI and G to be closed before the relay BP can close. Thus,the continuity of train line wires I or 2 and 6 and GS is ensured.Furthermore, the proper positioning of the reverser is ensured since thecoil of the switch LSI is energized through interlocks on the reversingswitch.

The closing of the switches LSI, G and JR connects the motors inseries-circuit relation through a circuit which extends from the trolleyconductor I6 through the current collecting device I5, the switch LSI,the resistor I8, conductor 48, the armature winding II of the motor MI,conductor 49, the series coil of the relay CR, conductor the reverser52, the series field winding I3, the reverser 52, conductor 53, theresistor 2I, conductor 54, the switch JR, the resistors 26 and 22,conductor 55, the reverser 56, the field winding I4, the reverser 56,conductor 51, the armature winding I2, conductor 58, and the switch G toground at IT.

When the controller AC is on the series position, the switch LS2 isclosed to shunt the resistor I8 from the motor circuit. The energizingcircuit for the actuating coil of the switch LS2 may be traced from thecontroller segment 35 through conductor 4, and interlock LSI I,conductor 6|, an interlock JR3, conductor 62, an interlock LS23,conductor 63, and the coil of the switch LS2 to negative. A holdingcircuit for the coil of the switch LS2 is established from the conductor38 through an interlock LS22 when the switch is closed.

Following the closing of the switch LS2, the resistor shunting switchesRI, R2, R3, R4 and R5 are closed in sequential relation under thecontrol of the limit relay CR. The energizing circuit for the actuatingcoil of the switch RI extends from the conductor 6I through an interlockLS24, conductor 64, contact members BP2 of the relay BP and the contactmembers of the relay CR, conductor 65, an interlock LSI5, conductor 66,an interlock LS2I, conductor 61, an interlock RI3, and the actuatingcoil of the switch RI to negative. A holding circuit is es tablishedfrom the conductor 45 through an interlock LSI I, conductor 68, and aninterlock RI2 when the switch is closed.

As explained hereinbefore, the switches R2. R3, R4 and R5 are closed byinterlock progression under the control of the limit relay CR. Theenergizing circuit for the actuating coil of the switch R2 extends fromthe conductor 66 through interlocks RII and R23, the coil of the switchR2, interlocks R3I, RM and R5I, conductor 69 and an interlock J I tonegative. A holding circuit for the switch R2 is established from theconductor 68 through an interlock R24 on the switch R2.

Following the closing of the switch R2, the actuating coil of the switchR3 is energized through a circuit which extends from the conductor 66through an interlock R22, the coil of the switch R3, the interlocks RMand R5I, the conductor 69 and the interlock J I to negative. A holdingcircuit for the switch R3 is established through an interlock R34.

The actuating coil of the switch R4 is energized through a circuit whichextends from the conductor 66 through interlocks R2I and R33, the coilof the switch R4, interlock RSI, conductor 69 and the interlock J I tonegative. A holding circuit for the switch R4 is established through aninterlock R43.

The actuating coil of the switch R5 is energized from the conductor 66through interlocks R32 and R42, the coil of the switch R5, conductor 69and the interlock J l to negative. It will be noted that the closing ofthe switch R5 opens the interlock R5I, thereby causing the switch R4 toopen. The switch R3 was opened following the closing of the switch R4and the switch R2 was opened following the closing of the switch R3 bythe opening of the interlocks on the proper switches. A holding circuitfor the switch R5 is established through an interlock R52 when theswitch is closed.

Following the closing of the switch R5, the switch J is closed duringbridging transition of the motors from series-circuit relation toparallei-circuit relation. The energizing circuit for the actuating coilfor the switch J extends from the conductor 66 through an interlock R44,conductor II, an interlock R54, conductor I2, an interlock MG4,conductor I3, and the coil of the switch J to negative. A holdingcircuit for the switch J extends from the conductor 45 through aninterlock J3, conductor I2, the interlock MG I, conductor I3, and thecoil of the switch J to negative. The closing of the switch J causes theopening of the switch JR by interrupting the energizing circuit for thecoil of theswitch JR which was previously established throughaninterlock J 4 on the switch J. As explained lhereinbefore, the switchJ shunts the resistor 20 from the motor circuit.

At this time, the switch MG is closed to complete the parallelconnections for the motors MI and M2. The energizing circuit. for theactuating coil of the switch MG may be traced from positive through thecontroller segment35, conductor 1, an interlock R53, conductor 15, aninterlock J2, conductor 16, an interlock JRI, conductor 11, and the coilof the switch MG to negative. A holding circuit is established from theconductor 44 through an interlock MG2 to the coil of the switch MG. Theclosing ofthe switch MG causes the opening of the switch J byinterrupting the holding circuit through the interlock MG4.

The motors Ml and M2 are now connected in parallel-circuit relation. Thecircuit through the motor Ml extends from the conductor 48 through thearmature winding l l, conductor 49, the series coil of the relay CR,conductor the'reverser 52, field winding 13, the reverser 52, conductor53, the resistor 2|, conductor 54, the switch MG, conductor 58 and theswitch G to ground at IT. The circuit for the motor M2 extends from theconductor 43 through the switch MG, conductor 18, the resistor 22,conductor 55, the reverser 56, the field winding 14, the reverser 55,armature winding 2, conductor 58 and the switch G to ground.

The acceleration of the motors is continued by the closing of theswitches R2,.R3, R4 and R5 to shunt the resistors 2| and 22 from themotor circuit. The resistor shunting switches are operated in sequentialrelation under the control of the relay CR in the manner previouslydescribed.

Following the closing of the switch R5, the actuating coil of the magnetvalve SF is energized to actuate the field shunting controllers FC! andFCZ from the full field position to the short field position, therebyshunting the motor field to intor '19, and the coil of the magnet valveFF to negative. The energizing circuit for the coil of the magnet valveSF extends from the conductor 66 through an interlock L825, conductor8i, an interlock MG5, conductor 82, an interlock R55, conductor 83 andthe coil of the magnet valve SF' to negative,

As indicated by the sequence chart, the field controllers are operatedstep-by-step, first to establish field shunting circuits for fieldwindings l3 and 14 when on position Fl and then to shunt the resistors26 and 28 from the field shunting circuits, thereby decreasing the fieldstrength of the motors and causing the speed of the motors to increasein a manner well known in the art. When the field shunting controls areon the short field position, the accelerating cycle is completed.

If it is desired to permit the vehicle to coast, the controller AC isactuated to the off position, thereby causing the opening of theswitches LS], LS2 andG to disconnect the motors from the power source.As explained hereinbefore, the holding coil HC'of the relay BP isenergized as the controller AC is being actuated towardthe off position.The energizing circuit for the coil HC may be traced from positivethrough a segment 84 on the controller AC, conductor 40, a segment 59 onthe controller R, conductor 3, an interlock 14 on the reversing switchFS, conductor 85 and the holding coil HC negative. In this manner, therelay BP is held closed during the coasting and braking cycles providedthe train line circuits function properly.

Following the opening of the switches, LSl and G, the switch BI isclosed to establish a dynamic braking circuit for the motors. Theenergizing circuit iorthe actuating coil of the switch Bl may be tracedfrom the conductor 85 through an interlock LSl2, conductor 80, contactmembers BP3, conductor 16, an interlock GI, conductor 86, an interlockB52, conductor 81, the actuating coil of the switch Bl, conductor 88, aninterlockBSl, conductor 89, and an interlock JR4 to negative.

At this time, the motors are connected for dynamic braking with theresistors l9, 2! and 22 connected in the dynamic braking circuits andwith the field controllers FCl and F02 on the short field position toshunt the motor field windings. Since the motors are operating with aweak field strength and the maximum amount of external resistance isconnected in the dynamic braking circuits, a relatively small amount ofbraking current circulates through the motors. However, this current isenough to give sufficient braking action to prevent the vehicle fromattaining an excessive speed during coasting.

The dynamic braking circuit for the motor M I extends from one terminalof the armature winding ll through conductor 48, the switch MG,conductor 18, the resistor 22, conductor 55, the reverser 56, the fieldwinding 14 of the motor M2, the reverser 5G, conductor 51, the switchBl, the resistor l9, conductor 9|, the resistor 25 and conductor 45 tothe other terminal'of the armature winding H. The circuit for the motorM2 extends from one terminal of the armature winding [2 throughconductor 51, the switch Bl, the resistor l9, conductor St, the resistor25, conductor 49, the series winding of the relay CR, conductor 5|, thereverser 52, the field winding (3 of the motor Ml the reverser 52,conductor 53, the resistor 2|, conductor 54, the switch MG and conductor58 to the other terminal of the armature winding l2.

During coasting of the vehicle, the operation of the field shuntingcontrollers EC! and F02 and the resistor shunting switches is under thecontrol of the spotting relay SR which, as explained hereinbefore, isresponsive to the motor speed. In this manner, the control apparatus ispositioned in accordance with the car speed and is prepared to respondpromptly whenever a brake application is called for.

As explained hereinbefore, the field shunting controllers FCl and FCZwere actuated to the short field position during acceleration of themotors. They remain in this position during coasting until the brakingcurrent decreases sufficiently to permit the spotting relay SE to dropto its lowermost position.

When the relay SR is in its lowermost position, an energizing circuit isestablished for the coil of the magnet valveFF, thereby causing thefield controllers F01 and FC2 to be actuated from the short fieldposition toward the full field position. The energizing circuit for thecoil of the magnet valve FF may be traced from the previously energizedconductor .88 through contact members BR4 of the relay BR, conductor 92,contact members SR1 of the relay SR, conductor 93,

contact segment 33 of the controller FCI, conductor I9 and the coil FFto negative.

In this manner the field controller is actuated toward the full fieldposition under the control of the spotting relay SR. When the fieldcontroller reaches the F2 position, the switch B2 is closed to shunt aportion of the resistor I9 from the motor circuits. The energizingcircuit for the actuating coil of the switch B2 may be traced from theconductor 93 through contact members BR3 of the relay BR, conductor 94,contact segment 34 of the controller FCI, conductor 95, an interlockBI2, conductor 96, an interlock B2I, the actuating coil of the switchB2, conductor 88, the interlock B5I, conductor 89, and the interlock JRI to negative. A holding circuit is established from the conductor 83through an interlock B22 when the switch B2 is closed.

The shunting of a portion of the resistor I9 from the motor circuitswill, of course, cause the motor current to increase, thereby actuatingthe relay SR to its uppermost position. When the relay SR is in itsuppermost position, an energizing circuit is established for the coil ofthe magnet valve SF, thereby causing the field controllers FCI and FC2to be operated toward the short field position. The circuit for the coilSF extends from the conductor 92 through contact members SR2, conductor91, the contact segment 3I and conductor 83 through the coil SF tonegative.

The field controller is stopped on position F4 by the interrupting ofthe circuit through the contact segment 3| and remains on this positionuntil the motor current decreases sufficiently to permit the relay SR todrop to its lowermost position. When the relay drops to its lowermostposition, the energizing circuit for the coil of the magnet valve FF isreestablished, thereby causing the field controller to be actuatedtoward the full field position.

When the field controller reaches position F2, the switch B3 is closedto shunt another portion of the resistor I9 from the motor circuits. Theenergizing circuit for the actuating coil of the switch B3 extends fromthe conductor 95 through interlocks B23 and B3I to the coil of theswitch B3 and thence through conductor 88, the interlock B5I, conductor89 and the interlock JR4 to negative.

In this manner, the resistor shunting switches are spotted duringcoasting by the operation of the field controller which, in turn, isunder the control of the spotting relay SR. The switches B4, B5 and B6may be closed by interlock progression under the control of the spottingrelay in a similar manner. If the vehicle speed continues to decreaseduring coasting, the switches RI to R5 will be closed under the controlof the spotting relay, thereby continuing to shunt resistance from themotor circuit in accordance with the vehicle speed.

If it is desired to decelerate the vehicle by dynamic braking, thecontroller BC is actuated to establish an energizing circuit for theactuating coil of the relay BR. This circuit extends from the conductor40 through a segment 98 on the controller BC, conductor 5 and the coilof the relay BR to negative.

When the relay BR is actuated to its uppermost position, the contactmembers BR3 and BR4 are opened and a contact member BRI is closed,.

thereby transferring the control of the resistor shunting switches andthe field shunting controller from the spotting relay SR to the cur- 10rent responsive relay CR. At this time a contact member BR5 is alsoclosed to energize the rate coil RC on the relay CR through a circuitwhich extends from positive through the contact member BR5, a conductorIUI, the rheostat 24, conductor I02 and the coil RC to negative.

It will be noted that the circuit through the variable resistor 23 wasinterrupted by the opening of an interlock LS26 when the switch LS2 wasopened at the beginning of the coasting operation. As explainedhereinbefore, the rheostat 24 is adjusted in accordance with theposition of the controller BC, thereby governing the dynamic brakingrate by changing the calibration of the relay CR.

The closing of the contact member BR5 on the relay BR also energizesboth the magnetizing coil M and the neutralizing coil N of the timedelay relay TD, thereby actuating this relay to its uppermost position.The energizing circuit for the magnetizing coil extends from theconductor I M through the segment 32 on the controller FCI, conductorI03 and the coil M to negative. The circuit for the neutralizing coil Nextends from the conductor IOI through a resistor I04 and the coil N tonegative.

At this time, the field shunting controller is actuated toward the fullfield position to increase the field strength of the motors, therebybuilding up the dynamic braking effect. The energizing circuit for thecoil of the magnet valve FF extends from the conductor 65 through acontact member BR'Z of the relay BR, conductor I05, the segment 33 onthe controller FCI, conductor I9, and the coil FF to negative. When thefield shunting controller is on position Fl, the circuit through thesegment 33 is interrupted, thereby stopping the field shuntingcontroller on position F I. At this time, the circuit through thesegment 32 for the magnetizing coil M of the time delay relay TD is alsointerrupted. The field shunting controller is held on position Fl for ashort time interval while the neutralizing coil N of the time delayrelay demagnetizes the relay sufficiently to permit it to drop to itslowermost posiiton. The delay in the operation of the field shuntingcontroller is to insure that the field strength of the motors has timeto build up before the operation of the resistor shunting switches isbegun.

When the contact member TDI on the relay TD is closed, within a shorttime after the deenergization of the magnetizing coil M, the coil of themagnet valve FF is energized'through a circuit which extends from theconductor I05 through the contact member IDI, conductor I9 and the coilFF to negative. The field shunting controller is then actuated to thefull field position.

When the field shunting controller is on position FF, the progressionwire 95 for the resistor shunting switches B2 to B5 is energized througha circuit which extends from the conductor I05 through contact membersTD2, conductor I06 and the segment 34 on the controller F01. Theenergization of the progression wire 95 causes the switches B2 to B6 tobe operated in the order shown in the sequence chart in Fig. 3 tocomplete the shunting of the resistor I9 from the motor circuits.

It will be understood that the sequential operation of the resistorshunting switches starts from the last switch which was closed duringthe coasting operation under the control of the spotting relay. Thus,the amount of resistance in the motor circuit has been proportionedaccording to the vehicles speed and. a smooth dynamic braking effect isobtained without delay when the full dynamic brake is applied.

When the switches have been closed to complete the shunting of theresistor 19 from the motor circuit under the control of the relay CR,the switches Rl to R are closed in the order shown in the sequence chartin Fig. 3 to shunt the resistors 2| and 22 from the motor circuit. Theprogression wire 65 for the switches Rl to R5 is energized through aninterlock G2 on the switch G. The resistor shunting switches areoperated by interlock progression under the control of the relay GR inthe manner hereinbefore described.

When the switches are closed toshunt the resistors 2| and 22 from themotor circuit, the dynamic braking cycle is completed and the vehiclemay be brought to a standstill by means of the air-brake system. Asdescribed in United States Patent 2,345,150, issued March 28, 1944 to G;R. Purifoy, the dynamic braking and the air-brake system may be socoordinated that the air-brake system takes effect as the dynamicbraking system fades out, thereby continuing the deceleration of thevehicle in a smooth manner.

The sequential operation of the switches Bl to B6 by interlockprogression has not been described in detail since it is similar inprinciple to the operation of the switches Rl to R5 which has beendescribed in detail. The interlocks on the switches and the circuitswhich control their operation are shown in the diagram and the switchesare operated in the order shown in the sequence chart in Fig. 3. Otherprotective interlocks shown in the diagram have not been described indetail since their function and method of operation are well known inthe" railway control art.

From the foregoing description, it is apparent that I have provided acontrol system which will permit a dynamic brake application only aftera normal power application, thereby insuring continuity of the controlcircuits, particularly the train line wires in a multiple-unit train,proper operation of the protective interlocking and correct polarity ofresidual motor voltage. The present system also provides for indicatingfailures of the equipment to function properly.

Since numerous changes may be made in the above-described constructionand diflferent embodiments of the invention may be made with.- outdeparting from the spirit and scope" thereof, it is intended that allmatter contained in the foregoing description or shown in theaccompanying drawing shall be interpreted as illustrative and not in alimiting sense.

I claim as my invention:

1. In a control system, in combination, a motor, main power conductors,control power conductors, switching means for connecting the motor tothe main power conductors, additional switching means for establishingdynamic braking connections for the motor, manually operable controlmeans for controlling the operation of said first-named switching means,relay means having contact members cooperating with said control meansin controlling the operation of said additional switching means, saidrelay means having a closing coil and a holding coil,- interlockingcontact means actuated by said firstnamed switching means andcooperating with said control means to control the energization of 12said closing coil through said control power conductors, and contactmeans on said control means for controlling the energization of saidholding coil.

2. In a control system, in combination, a motor, main power conductors,control power conductors, switching means for connecting the motor tothe main power conductors, additional switching means for establishingdynamic braking. connections for the motor, manually operable controlmeans for controlling the operation of said first-named switching means,relay means having contact members cooperating with said control meansin controlling the operation of said additional switching means, saidrelay means having a closing coil and a holding coil, interlockingcontact means actuated by said firstnamed switching means andcooperating with said control means to control the energization of saidclosing coil through said control power conductors, and contact means onsaid control means; for controlling the energization of said holdingcoil, said closing coil being energized only when said control means isactuated to apply power to'the motor.

3. In a control system, in combination, a motor, main power conductors,control power conductors, switching means for connecting the motor tothe main power conductors, additional switching means for establishingdynamic braking connectionsfor the motor, manually operable controlmeans for controlling the operation of said firstnamed switching means,relay means having contact members cooperating with said control meansin controlling the operation of said additional' switching means, saidrelay means having a closing coil and a holding coil, interlockingcontact means actuated by said first-named switching means andcooperating with said control means to control the energization of saidclosing coil through said control power conductors, and contact means onsaid control means for controlling. the energization of said holdingcoil, said closing coil being energized only when said control means isactuated to apply power to the motor,. said holding coil being energizedprior to the deenergization of said closing coil by the actuation ofsaid control means to establish dynamic braking connections for themotor.

4. In a control system, in combination, a motor, main power conductors,control power conductors, switching means for connecting the motor toth'e" main power conductors, additional switchingmeans for establishingdynamic braking connectionsfor the motor, resistance means forcontrolling the motor current, a plurality of switches for shunting saidresistance means step-by-step, a relay responsive to the motor current,relay means having contact members for controlling the operation-of saidadditional switching means, said relay means cooperating with said relayin controlling the operation of said switches, and interlocking contactmeansactuated by said firstnamed switching means for controlling theenergization of said relay means through said control power conductors.

5; In a control system, in combination, a motor; main power conductors,control power conductors, switching means for connecting the motor tothe main power conductors, additional switching means for establishingdynamic braking connections for the motor, manually operable controlmeans for controlling the operation of said first named switching means,relay means having contact members cooperating with said control meansin controlling the operation of said additional switching means,resistance means for controlling the motor current, a plurality ofswitches for shunting said resistance means step-by-step, a relayresponsive to the motor current and cooperating with said relay means incontrolling the operation of said switches, and interlocking contactmeans actuated by said first-named switching means for controlling theenergization of said relay means through said control power conductors.

6. In a control system, in combination, a motor, main power conductors,control power conductors, switching means for connecting the motor tothe main power conductors, additional switching means for establishingdynamic braking connections for the motor, manually operable controlmeans for controlling the operation of said first-named switching means,relay means having contact members cooperating with said control meansin controlling the operation of said additional switching means,resistance means for controlling the motor current, a plurality ofswitches for shunting said resistance means stepby-step, a relayresponsive to the motor current and cooperating with said relay means incontrolling the operation of said switches, and interlocking contactmeans actuated by said firstnamed switching means and cooperating withsaid control means in controlling the energization of said relay meansthrough said control power conductors.

7. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching means for establishing dynamic braking connectionsfor the motor, a plurality of train line wires, manually operablecontrol means for controlling the operation of said firstnamed switchingmeans through said wires, relay means having contact members cooperatingwith said control means in controlling the operation of said additionalswitching means, and interlocking contact means actuated by saidfirstnamed switching means for controlling the energization of saidrelay means.

8. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching means for establishing dynamic braking connectionsfor the motor, a plurality of train line wires, manually operablecontrol means for controlling the operation of said firstnamed switchingmeans through said wires, relay means having contact members cooperatingwith said control means through said wires in controlling the operationof said additional switching means, and interlocking contact meansactuated by said first-named switching means and cooperating with saidcontrol means through said wires in controlling the energization of saidrelay means.

9. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching means for establishing dynamic braking connectionsfor the motor, reversing means for the motor, manually operable controlmeans, interlocking contact means actuated by the reversing means andcooperating with the control means in controlling the operation of saidfirstnamed switching means, relay means having contact members forcontrolling the operation of said additional switching means, andinterlocking contact means actuated by said first-named 14 switchingmeans for controlling the energization of said relay means.

10. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching means for establishing dynamic braking connectionsfor the motor, reversing means for the motor, manually operable controlmeans, interlocking contact means actuated by the reversing means andcooperating with the control means in controlling the operation of saidfirst-named switching means, relay means having contact memberscooperating with said control means in controlling the operation of saidadditional switching means, and interlocking contact means actuated bysaid firstnamed switching means and cooperating with said control meansin controlling the energization of said relay means.

11. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching means for establishing dynamic braking connectionsfor the motor, relay means having contact members for controlling theoperation of said additional switching means, interlocking contact meansactuated by said first named switching means for controlling theenergization of said relay means, and indicating means energized throughsaid relay means.

12. In a control system, in combination, a motor, power conductors,switching means for connecting the motor to the power conductors,additional switching mean for establishing dynamic braking connectionsfor the motor, relay means having normally open contact members forcontrolling the operation of said additional switching means,interlocking contact means actuated by said first-named switching meansfor controlling the energization of said relay means, normally closedcontact members on said relay means, and indicating means energizedthrough said normally closed contact members.

13. A motor-controlling assembly, including the combination, with amotor-means to be controlled, of a supply-circuit for the motor-means;power-switch means for establishing a power-cir cuit for energizing themotor-means from the supplycircuit; braking-switch means forestablishing a dynamic-braking circuit for the motormeans; anaccelerating-controller having an ofiposition and an on-position orpositions; a motoring-circuit on-position controller-contact means,which is closed when said accelerating-controller is moved from its ofiposition; control-circuit means for effecting a closure of saidpowerswitch means so as to establish a power-circuit for the motor-meansin joint response to an open position of a braking-switch means, and toan on-position of said accelerating-controller, in cluding a response tosaid motoring-circuit onposition controller-contact means; abraking-circuit off-position controller-contact means, which is closedwhen said accelerating-controller is in its off-position, there being anoverlapping point when both said motoring-circuit and brakingcircuitcontroller-contact means are closed; a protective relay; control-circuitmeans for effecting an actuation of said protective relay in response tothe establishment of a power-circuit for said motor rneans;holding-means for holding said protective relay in its actuated positionin response to a closure of said braking-circuit offpositioncontroller-contact means, said holdingmean being efiective only aftersaid protective relay haspreviously been moved to its actuated position;and control-circuit means for effecting a closure of said braking-switchmeans so as to establish a dynamic-braking motor-circuit in jointresponse to an off-position of said accelerating-controller, to an openposition of a powerswitch means, and. to an actuated position of saidprotective relay.

14. A motor-controlling assembly, including the combination, with amotor-means to be controlled, of a supply-circuit for the motor-means;power-switch means for establishing a power-circuit for energizing themotor-means from the supply-circuit; braking-switch mean forestablishing a dynamic-braking circuit for the motormeans; progressivelyoperating current-controlling means for controlling the motor-current;progressively operating braking-controlling means for controllingdynamic-braking motorconditions; a limit-relay or relays energized to beresponsive to conditions which accompany excessive torque in themotor-means; an acceleratingcontroller having an oiT-position and anon-position or positions; a braking-controller having an oiT-positionand an on-position or positions; a motoring-circuit on-positioncontroller-contact means, which is closed When saidacceleratingcontroller is moved from its off-position; control-circuitmeans for effecting a closure of said power-switch means so as toestablish a powercircuit for the motor-means in joint response to anopen position of a braking-switch means, and to an on-position of saidaccelerating-controller, including a response to said motoring-circuitonposition controller-contact means; a brakingcircuit oiT-positioncontroller-contact means, which is closed when saidaccelerating-controller is in its off-position, there being anoverlapping point when both said motoring-circuit and braking-circuitcontroller-contact means are closed; a protective relay; control-circuitmeans for effecting an actuation of said protective relay in response tothe establishment of a power-circuit for said motor-means; holding-meansfor holding said protective relay in its actuated positon in response toa closure of said braking-circuit 01T- position controller-contactmeans, said holdingmeans being effective only after said protectiverelay has previously been moved to its actuated position;control-circuit means for causing a progressing operation of saidprogressively operating current-controlling means in joint response toan on-position of said accelerating-controller and to the position of alimit-relay; control-circuit means for eflecting a closure of saidbrakingswitch means so as to establish a relatively Weak dynamic-brakingmotor-circuit to joint response to an off-position of saidaccelerating-controller, to an open position of a power-switch means,and to an actuated position of said protective relay; andcontrol-circuit means for causing a progressing operation of saidprogressively operating braking-controlling means in joint response toan on-position of said braking-controller, to an actuated position ofsaid protective relay, and to the position of a limit-relay.

15. A motor-controlling assembly, including the combination, with amotor-means to be controlled, of a supply-circuit for the motor-means;power-switch means for establishing a powercircuit for energizing themotor-means from the supply-circuit; bra-king switch means forestablishing a dynamic-braking circuit for the motormeans; progressivelyoperating current-controlling means for controlling the motor-current;progressively operating braking-controlling means for controllingdynamic-braking motorconditions; a, limit-relay or relays energized tobe responsive to conditions which accompan excessive torque in themotor-means; an accelerating-controller having an off-position and anonposition or positions; a braking-controller having an off-position andan on-position or positions; a motoring-circuit on-positioncontroller-contact means, which is closed when saidacceleratingcontroller is moved from its off-position; control-circuitmeans for effecting a closure of said powersivitch means so as toestablish a powercircuit or the motor-means in joint response to an openposition of a braking-switch means, and to an on-position of saidaccelerating-controller, including a response to said motoring-circuitonposition controller-contact means; a brakingcircuit off-positioncontroller-contact means, which is closed when saidaccelerating-controller is in its oii-position, there being anoverlapping point when both said motoring-circuit and braking-circuitcontroller-contact means are closed; a protective relay; control-circuitmeans for offooting an actuation of said protective relay in response tothe establishment of a power-circuit for said motor-means; holding-meansfor holding said protective relay in its actuated position in responseto a closure of said braking-circuit obi-position controller-contactmeans, said holding-means being effective only after said protectiverelay has previously been moved to its actuated position;control-circuit means for causing a progressing operation of saidprogressively operating current-controlling mean in joint response to anon-position of said acceleratingcontroller, to an actuated position ofsaid protective relay, and to the position of a limit-relay;control-circuit means for efiecting a closure of said braking-switchmeans so as to establish a relatively weak dynamic-braking motor-circuitin joint response to an off-position of said accelerating-controller, toan open position of a power-switchmeans,,and to an actuated position ofsaid protective relay; and control-circuit means for causing aprogressing operation of said progressively operatingbraking-controlling means in joint response to an on-position of saidbraking-controller, to an actuated posiiton of said protective relay,and to the position of a limitrelay.

LYNN G. RILEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,134,545 Austin Oct. 25, 19382,331,228 Purifoy Oct. 5, 1943

